An electronic calendar provides an alternative and/or a complement to a standard paper calendar. An input device, such as, for example, a keyboard, a mouse, or a touch screen may be used to manually create entries in the electronic calendar. If the entries are of interest to multiple entities, then each entity may manually create corresponding entries in their calendar. If the original entries change, then each of the interested entities can be informed of the change, and the calendars of each of the entities can be manually updated.